1. Field of the Invention
The present invention relates to weight training and weight training machines of the type having a vertical stack of weights.
2. Description of the Prior Art
In our increasingly health conscious society, weight lifting remains one of the most popular methods of increasing muscle strength and muscle tone. Weight lifting is no longer the sole province of the body builder or serious athlete--many Americans now incorporate some form of weight lifting exercises into their workouts. As a result, weight training machines, such as those using a vertical stack of weights, have become increasingly popular because of their ease of use and ability to isolate specific muscle groups during an exercise.
The goal of weight lifting is to fatigue a particular muscle group through a selected weight lifting exercise thereby stimulating muscle growth within the muscle group. To achieve the maximum benefit from weight lifting exercises, the weight lifter completes multiple sets of repetitions for each weight lifting exercise in order to completely fatigue the muscle group being exercised. The weight lifter is required to continuously change the amount of weight being used between sets to insure completion of the set, while also maintaining maximum muscle exertion during a set. As a result, weight lifters are required to spend considerable time in the gym to achieve the maximum workout. For this reason, there is a need for a weight training device that allows the user to achieve the maximum exertion for each repetition of each exercise, thus minimizing the exercise time the user needs to devote to stimulating new muscle growth.
Add-on weights or auxiliary weights which may be added to the weight stacks of weight training machines to incrementally increase the amount of weight available to the user are known in the prior art. U.S. Pat. No. 772,906, issued to Robert Reach on Oct. 18, 1904, shows a weight for use in a weight lifting machine having a recess in one face and a projection on the opposite face. Sliding bolts are attached to the weight and are adapted to engage the projection of an adjacent weight to permit connection of adjacent weights. U.S. Pat. No. 4,971,305, issued to Brian G. Rennex on Nov. 20, 1990, shows a variable add-on weight device which enables weight trainers to select a particular weight and to make this weight selection with smaller weight increments. The device includes a stack of weight pieces or units which stick together and can be separated into multiple parts. U.S. Pat. No. 5,256,121, issued to Eric Brotman on Oct. 26, 1993, shows an auxiliary weight system for use with free weights or weight training machines. The auxiliary weights are formed with small weight values and may be magnetically secured to the main weights to change the aggregate value being lifted by small amounts. None of the above referenced patents teach or suggest a self-releasing pin for a weight training machine.
U.S. Pat. No. 4,627,615, issued to Paul S. Nurkowski on Dec. 9, 1986, shows a progressive weight resistance weight lifting mechanism having a base, a plurality of spaced vertical guide members, a carriage vertically reciprocating along the guide members and a plurality of weight stacks supported by the base. An apertured selector post is slidably disposed through each stack and has a first pin for attaching a selected subset of weights from the stack for upward movement. A second pin on each selector post is provided for locking a slidable collar at selected positions on the post above the carriage. The collars may thus be set at different distances above the carriage. The upward-travelling carriage engages each collar in sequence to serially lift the associated weight stacks. The user thereby experiences progressively increasing weight resistance during the course of a single repetition. Nurkowski does not teach or suggest a self-releasing pin for a weight training machine.
U.S. Pat. No. 4,746,113, issued to Robert M. Kissel on May 24, 1988, shows an automatically adjustable weight changing system including a body carrying a plurality of pins for engagement with the openings of a weight stack. Upon receipt of a signal representative of momentary muscle failure of the user, solenoid operated pin controllers retract the pin supporting the stack of weights being lifted and insert a higher pin in the weight stack to automatically decrease the weights being lifted. U.S. Pat. No. 5,350,344, issued to Robert M. Kissel on Sept. 27, 1994, shows the automatically adjustable weight changing system described in Kissel '113, however, a two-position or double action actuator or solenoid is provided. Kissel '113 and Kissel '344 do not teach or suggest a self-releasing pin for a weight training machine having a retaining member pivotally attached to the shaft of the self-releasing pin.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.